A standard solution of FeSCN2+ is prepared by combining 9.00 mL of 0.200 M Fe(NO3)3 w/1.00 mL of 0.0020 M KSCN. The equilibrium concentration of FeSCN2+ ([FeSCN2+]std) for this standard solution is assumed to be
____ M.
This post has appeared here for the last 4-5 days but with different numbers. The process of working it, however, is the same. In this case, onloy half the problem is posted.
Use the standard and Beer's Law to determine the constant a in A = abc. You know A, you know b (the cell length), and you can calculate c (from the problem).
I would start by determining mols Fe(NO3)3 and mols KSCN. You know they will form ?? mol FeSCN^+2. The final concn will be mols/L.
why is radioactive waste stored underground
is it because it is a harmful substance
Yes, it is harmful. It has long half lives and sticks around for 100s and 1000s of years (or longer). The idea of putting it underground is to use the earth plus man-made barriers (containers) to shield the radiation from the population. From what I've read, the project is far behind schedule, far behind in the technology, cost overruns are out of sight, and many of the temporary containers are starting to leak.
To find the equilibrium concentration of FeSCN2+ ([FeSCN2+]std), we can use the concept of stoichiometry and the principles of chemical equilibrium.
First, let's write the balanced chemical equation for the reaction between Fe(NO3)3 and KSCN:
Fe(NO3)3 + KSCN --> FeSCN2+ + 3 KNO3
From the balanced equation, we can see that the molar ratio between Fe(NO3)3 and FeSCN2+ is 1:1. This means that the moles of Fe(NO3)3 used will be equal to the moles of FeSCN2+ formed.
Step 1: Calculate the moles of Fe(NO3)3 used:
Moles of Fe(NO3)3 = volume (in liters) x concentration
Moles of Fe(NO3)3 = 9.00 mL x (1 L/1000 mL) x 0.200 M
Moles of Fe(NO3)3 = 0.0018 moles
Step 2: Calculate the moles of FeSCN2+ formed:
Moles of FeSCN2+ = moles of Fe(NO3)3 used (from Step 1)
Moles of FeSCN2+ = 0.0018 moles
Step 3: Calculate the concentration of FeSCN2+ in the standard solution:
Volume of the standard solution = sum of the volumes of Fe(NO3)3 and KSCN = 9.00 mL + 1.00 mL = 10.00 mL
Concentration of FeSCN2+ (in M) = moles/V (volume in liters)
Concentration of FeSCN2+ = 0.0018 moles / (10.00 mL x (1 L/1000 mL))
Concentration of FeSCN2+ = 0.180 M
Therefore, the equilibrium concentration of FeSCN2+ ([FeSCN2+]std) in the standard solution is 0.180 M.